HIGH-DOSE CONSOLIDATION CHEMOIMMUNOTHERAPY AND PERIPHERAL BLOOD STEM CELL (PBSC) COLLECTION: Approximately 4 weeks after completion of chemoimmunotherapy, patients receive high-dose consolidation chemoimmunotherapy comprising cytarabine IV over 2 hours and etoposide phosphate IV continuously on days 1-4, and rituximab IV over 4-6 hours on days 5 and 12 OR 6 and 13. Beginning on day 14 and continuing until completion of PBSC collection, patients receive G-CSF SC QD. Once blood counts recover, patients undergo 1-3 leukapheresis procedures for collection of PBSCs on days 22-25.